In various kinds of devices such as semiconductors, various kinds of metal thin films are used for satisfying the required properties of the devices. As a method for forming these metal thin films, a chemical deposition method such as a CVD method, which is capable of forming a uniform and homogeneous film at a high film formation rate and in conformity with even a three-dimensional shape etc. of a device, is used.
As a metal complex that is a raw material in formation of a metal thin film by the chemical deposition method, a complex including a plurality of ligands such as cyclopentadienyl with one metal as a central metal (nucleus) (hereinafter, referred to as a mononuclear complex) as shown in the following chemical formula 1 is known. A complex including a plurality of metals of the same kind as central metals (hereinafter, referred to as a homogeneous polynuclear complex) as shown in the following chemical formula 2 is also known.

In formation of a metal thin film for use in a device such as a semiconductor by use of the above-mentioned mononuclear complex or homogeneous polynuclear complex as a chemical deposition raw material, a thin film including a plurality of kinds of metals is often applied. In a device having a reduced size and weight, such as a semiconductor, a plurality of metal thin films are applied, and deposited for imparting various kinds of required properties, so that the device is densified and highly integrated while attaining required properties. For example, when copper is used as a wiring material of a semiconductor, a structure is used in which a thin film of MnO, MnSiO or the like as a barrier layer for preventing diffusion of copper, and a thin film of ruthenium and the like as a base for introducing the barrier layer are deposited together.
As an example of forming a thin film including a plurality of metals as described above, mention is made of Patent Document 1, Patent Document 2 and so on. Patent Document 1 suggests that a plurality of mononuclear complexes etc. are provided, and metal thin films are sequentially deposited from the complexes to form a plurality of metal layers each including a single metal. Patent Document 2 suggests that a plurality of mononuclear complexes are mixed beforehand, and dissolved or emulsified to obtain an inert liquid, and from the inert liquid, a composite metal thin film containing a plurality of metals is formed.